Rep. Dana Rohrabacher, R-Calif., met Prime Minister Nouri al-Maliki in Baghdad Friday and told him his House subcommittee is investigating clashes between the Iraqi army and Iranian exiles, CNN reported.
The April attack on the Mojahedin-e Khalq's Camp Ashraf left 34 people dead and more than 200 wounded.
The MEK was allied with Saddam Hussein and is officially considered a terrorist group by the U.S. government, but many prominent Americans now support it as an enemy of Iran. Maliki's Shiite government is friendly to Iran.
Iraq then told the U.S. Embassy Rohrabacher and his five colleagues were no longer welcome in the country. Maliki also refused to let the congressmen visit Camp Ashraf. Iraq wants to expel the 3,000 MEK members.
Embassy spokesman David Ranz said Saturday: "Congressional visitors do not necessarily express the views of the U.S. administration or even a majority of Congress. The visitors this weekend made that clear in their remarks."
Rohrabacher also reportedly said Iraq should repay the United Stets some of the cost of the war.